Use twrp for instaling miui 7 v5.12.31...safe rom 5.12.29 n update rom 5.12.31 in sd card
1. go to twrp recovery
2. Wipe chace, dalvik, data, system..next reboot...no os is oks
3. Back to recovery twrp n klik instal zip..use rom 5.12.29 in sdcard ...(rilexs...wait n see)
4. After finish wipe...